The problem involved in disposal of solid municipal waste (garbage) is presently solved by the so-called "sanitary landfill" method, incineration, disposal in abandoned mines, merely dumping, etc.
These methods are wasteful, in terms of the loss of the energy content of such materials, the dissemination of otherwise valuable resources, and in the case of incineration, the loss of the energy stored as carbohydrates and fixed nitrogen compounds represents a fearful waste, as these materials have to be resynthesized by either nature or man in order to replace the supply of foodstuffs available to the human race.
Several attempts have been made to recover at least a part of the energy values in such materials by rather exotic processes, e.g., the hydrogenation thereof under conditions of high temperatures and pressures, by direct gasification, by drying and burning them together with other fossil fuels in electrical power houses, etc. The disadvantages of such systems include high capital investments for special reactors, the production of considerable char instead of the primary fuel product, and the necessity for special flue-gas purification systems in order to meet air-purity standards.